Colvin combined with Tommy Palica and Andy Loomis on a two-hitter as the Class A Advanced Threshers rolled to a 9-0 blanking of the Fort Myers Miracle.
Colvin, the Phillies' No. 3 prospect, left with tightness in his groin after completing three one-hit frames. He allowed Anderson Hidalgo's leadoff single in the third and nothing else while striking out four.
Palica (1-0) came on in the fourth and kept the run on outs going. The left-hander yielded Josmil Pinto's two-out single in the fifth, then retired his final 10 batters.
Selected by the Braves in the 10th round of the 2007 Draft, Palica had allowed at least one run in five of his first six relief appearances this season. He carried a 13.90 ERA into Friday's outing.
Loomis, another lefty, pitched a 1-2-3 ninth to complete Clearwater's eighth shutout of the season and third against the Miracle. The Marlins' 16th-round selection in the 2008 Draft, he's made 10 consecutive appearances without alowing a run.
The Threshers scored six runs off Miracle starter Edgar Ibarra (2-7), who retired just one batter in the opening inning.
Seven of the nine members of the Threshers' lineup collected at least two hits. Jonathan Singleton, MLB.com's No. 20 prospect, went 1-for-3 with two walks and a pair of runs scored.